title: T lymphocyte-macrophage interactions in cellular antibacterial immunity.
abstract: Acquired resistance to facultative intracellular bacteria depends on a bicellular mechanism whereby specific T lymphocytes activate macrophages for enhanced bacteriocidal capacity. In vivo, protection is paralleled by delayed-type hypersensitivity. In vitro correlates are specific T lymphocyte proliferation and interleukin induction. Macrophage activation results from complex cell interactions involving both T lymphocytes and macrophages. Although such interactions are not yet fully understood, it appears likely that interleukin-facilitated collaboration between Lyt 1 and Lyt 123 T lymphocytes is required. Most probably, H2-restricted interactions between antigen-presenting mononuclear phagocytes and Lyt 1 T lymphocytes induce secretion of interleukins which further recruit additional Lyt 1 T lymphocytes from the Lyt 123 T lymphocyte set. In this way, the pool of Lyt 1 T lymphocytes capable of attracting and activating macrophages at the site of bacterial and implantation via lymphokines (macrophage activating factor, migration inhibition factor) could be markedly enhanced.
mesh_terms: D000818:Animals; D001424:Bacterial Infections / Q000276:immunology; D002450:Cell Communication; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007111:Immunity, Cellular; D007375:Interleukin-1; D007376:Interleukin-2 / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000276:immunology; D008222:Lymphokines / Q000494:pharmacology; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D009000:Monocytes / Q000276:immunology; D010586:Phagocytes / Q000276:immunology; D011453:Prostaglandins / Q000494:pharmacology; D011506:Proteins / Q000494:pharmacology; D051381:Rats; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*
chemical_list: D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1; D007376:Interleukin-2; D008222:Lymphokines; D011453:Prostaglandins; D011506:Proteins